CVE-2025-11639

Executive Summary

CVE-2025-11639 identifies a critical security vulnerability in Tomofun Furbo 360 and Furbo Mini pet cameras. The flaw resides in the collect_logs.sh script, which handles debug log uploads to an S3 bucket. The manipulation of this component leads to insecure storage of sensitive information, potentially exposing device logs, credentials, or other confidential data. The attack vector is local, meaning an attacker with physical or local network access to the device can exploit this vulnerability. The vendor, Tomofun, has not responded to disclosure attempts, and no patch is currently available. This report provides a comprehensive technical analysis, detection strategies, and exploitation guidance for security professionals.

Supply Chain & Package Security

This vulnerability is not related to a package manager (NPM, PyPI, Go, Ruby) but involves a proprietary firmware component. The supply chain risk is limited to the physical device and its firmware distribution. Users should verify the integrity of firmware updates from Tomofun's official channels and monitor for any unauthorized modifications.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which is likely a placeholder or unassigned. Based on the vulnerability characteristics, a reasonable assessment would be:

• Attack Vector (AV): Local (L) – Requires local access to the device.
• Attack Complexity (AC): Low (L) – The script is accessible and manipulable.
• Privileges Required (PR): Low (L) – May require user-level access.
• User Interaction (UI): None (N) – No user action needed beyond initial access.
• Scope (S): Unchanged (U) – The vulnerable component is within the device.
• Confidentiality (C): High (H) – Sensitive information is exposed.
• Integrity (I): Low (L) – Data integrity may be affected.
• Availability (A): None (N) – No impact on availability.

Estimated CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N Estimated Score: 5.6 (Medium)

Threat Level: Medium. The local attack vector reduces the immediate risk, but the potential exposure of sensitive data (e.g., Wi-Fi credentials, cloud tokens) makes it a significant concern for affected users.

Deep Dive & Mechanics

The vulnerability is in the collect_logs.sh script, which is part of the debug logging mechanism. This script is responsible for collecting device logs and uploading them to an S3 bucket for troubleshooting. The insecure storage of sensitive information occurs because:

1. Hardcoded Credentials: The script may contain hardcoded AWS S3 bucket names, access keys, or secret keys.
2. Insecure Permissions: The S3 bucket might be publicly accessible or have overly permissive access controls.
3. Log Content: The logs collected may include sensitive data such as Wi-Fi passwords, API tokens, or device configuration details.

An attacker with local access (e.g., via SSH, physical USB, or local network) can:

• Read the collect_logs.sh script to extract S3 bucket credentials.
• Access the S3 bucket directly if credentials are exposed.
• Retrieve logs from the bucket, potentially containing sensitive information from multiple devices.

The firmware versions affected are Furbo 360 up to FB0035_FW_036 and Furbo Mini up to MC0020_FW_074. No patch is available, and the vendor has not responded.

Vulnerable vs. Patched Code

Since no patch is available, a comparison cannot be made. However, the vulnerable code likely contains:

Vulnerable (collect_logs.sh):

#!/bin/bash
# Hardcoded S3 bucket and credentials
BUCKET="furbo-debug-logs"
ACCESS_KEY="AKIAIOSFODNN7EXAMPLE"
SECRET_KEY="wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"

# Collect and upload logs
tar -czf /tmp/logs.tar.gz /var/log/
aws s3 cp /tmp/logs.tar.gz s3://$BUCKET/device-$(hostname)-$(date +%Y%m%d).tar.gz

Patched (hypothetical):

#!/bin/bash
# Use IAM roles or environment variables for credentials
BUCKET="furbo-debug-logs"

# Collect and upload logs with proper permissions
tar -czf /tmp/logs.tar.gz /var/log/
aws s3 cp /tmp/logs.tar.gz s3://$BUCKET/device-$(hostname)-$(date +%Y%m%d).tar.gz --acl bucket-owner-full-control

The patched version would avoid hardcoded credentials and enforce proper S3 bucket policies.

Exploitation & Lab Setup

Red Team

Objective: Extract sensitive information from the S3 bucket.

Prerequisites:

• Local access to a vulnerable Furbo device (e.g., via SSH or physical console).
• Basic knowledge of AWS CLI.

Steps:

1. Gain local access to the device (e.g., default credentials, SSH exploit).
2. Locate and read the collect_logs.sh script:

   cat /path/to/collect_logs.sh
   

3. Extract the S3 bucket name and credentials.
4. Use AWS CLI to list and download logs:

   aws s3 ls s3://furbo-debug-logs/
   aws s3 cp s3://furbo-debug-logs/device-1234-20250301.tar.gz .
   

5. Analyze the downloaded logs for sensitive data (e.g., Wi-Fi passwords, cloud tokens).

Lab Setup:

• Use a virtual machine or physical Furbo device with vulnerable firmware.
• Set up a local network to simulate the attack.
• Use tools like nmap to discover the device and ssh for access.

Blue Team

Objective: Detect and mitigate exploitation attempts.

Detection:

• Monitor for unauthorized access to the device (e.g., failed SSH attempts).
• Monitor network traffic for unusual S3 bucket access (e.g., from unexpected IPs).
• Use file integrity monitoring (FIM) to detect changes to collect_logs.sh.

Mitigation:

• Isolate vulnerable devices on a separate VLAN.
• Restrict local access to the device (e.g., disable SSH, change default passwords).
• Monitor S3 bucket access logs for unauthorized activity.
• If possible, block outbound traffic to S3 from the device.

Indicators of Compromise (IOCs)

• File Hashes (collect_logs.sh):
  • MD5: d41d8cd98f00b204e9800998ecf8427e (example, replace with actual)
  • SHA256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 (example)
• S3 Bucket Names: furbo-debug-logs (example)
• Network Indicators:
  • Outbound connections to s3.amazonaws.com or specific S3 endpoints.
  • Unusual DNS queries for S3 bucket names.
• Process Indicators:
  • Execution of aws s3 cp or aws s3 ls commands.
  • Running collect_logs.sh script.

Detection Engineering

YARA Rule

rule CVE_2025_11639_Furbo_Logs
{
    meta:
        description = "Detects hardcoded S3 credentials in collect_logs.sh"
        author = "Valters IT"
        date = "2025-03-01"
        cve = "CVE-2025-11639"
    strings:
        $s3_bucket = "s3://" nocase
        $access_key = "AKIA" nocase
        $secret_key = "wJalrXU" nocase
    condition:
        any of them
}

Sigma Rule

title: Detection of Furbo Debug Log S3 Bucket Access
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects attempts to access the Furbo debug log S3 bucket
author: Valters IT
date: 2025-03-01
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/aws'
        CommandLine|contains: 's3://furbo-debug-logs'
    condition: selection
falsepositives:
    - Legitimate debugging activities
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET 443 (msg:"CVE-2025-11639 Furbo S3 Bucket Access"; flow:to_server; content:"s3.amazonaws.com"; http_host; content:"furbo-debug-logs"; http_uri; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Devices: Place vulnerable Furbo devices on a separate network segment with restricted outbound access.
2. Disable Debug Logging: If possible, disable the collect_logs.sh script or remove its execution permissions.
3. Change Default Credentials: Ensure all devices have strong, unique passwords for local access.
4. Monitor S3 Buckets: If you have access to the S3 bucket, review its permissions and access logs for unauthorized activity.

Long-Term Fix:

• Vendor Patch: Await an official firmware update from Tomofun. Since the vendor has not responded, consider alternative solutions.
• Custom Firmware: If technically feasible, develop a custom firmware that removes or secures the debug logging functionality.
• Device Replacement: Evaluate replacing the device with a more secure alternative.

Workaround:

• Block outbound traffic to S3 endpoints from the device using a firewall.
• Use network monitoring to detect any attempts to access S3 buckets.

Valters IT
Securing Digital Frontiers